class_docstr: Feature loader that load external features store in certain format. 
  Currently support pickle, npy and npz format.
code: def process(self, file_path: str) -> torch.Tensor:
      features = self.load_feature_from_file(file_path)
      features = self.process_segment(features)
      return features
  
file_path: NeMo/nemo/collections/asr/parts/preprocessing/feature_loader.py
imports: from typing import Optional
  import numpy
  import torch
label_desc: Use image node_id 4 for calling the ExternalFeatureLoader obj's underlying member method code with example usage: obj.process(file_path) and returns: features